This week in Second Opinion we go a little further with all things smokable. Why do people do it?Mel, Jess & Dave Mason ask Dr Ken Starr some questions about addiction, Dopamine and how receptors work. We revisit Medical Marijuana with a personal story about pain relief and speak to Toxicologist, and Associate Prof of Emergency Medicine, USC, Dr Sean Patrick Nordt about the effects of Hookah and carbon monoxide.